DESCRIPTIONS OF GENERA AND SPECIES 663 



Genus DIACHAETA, BENHAM. 

 Syn. Pontoscolex, SCHMABDA (in part.). 



DEFINITION. Prostomium absent ; setae irregular from the first. Mucous gland 

 present. Calciferous glands absent. Sperm-sacs very long. Spermathocao two 

 or three pairs. Testes and funnels, one pair. 



This genus is very near to Pontoscolex and to Onychochaeta. It differs from 

 the former chiefly in the facts that the setae are irregular from the first, and that 

 there are no glands connected with the posterior nephridia. Our knowledge of 

 the genus is chiefly derived from BENHAM'S description of D. thomasii; my own 

 notes upon a second species are not so full. I found, however, that the setae are 

 occasionally bifid, a point not referred to by BENHAM ; this brings the genus 

 into somewhat nearer proximity to Pontoscolex, as does also the fact that the 

 end of the nephridia is surrounded by the cup-shaped body so characteristic of 

 Pontoscolex. As will be seen in the following lines, there is no possibility of 

 confusing the two species of the genus. 



(1) Diachaeta thomasii, BENHAM. 

 D. Thomasii, BENHAM, Q. J. M. S., vol. xxvii, 1887, p. 89. 



Definition. Length, about 3 inches; diameter, about J inch; number of segments, 335. 

 Clitellum, XX-XXXIII, complete. Septa VI/XI very much thickened. Gizzard in VI ; 

 intestine begins in XI. Last heart in XI. Sperm-sacs extend from XII-XXXVIII, 

 constricted at the septa. Spermathecae in FT, VII, VIII. Hob. St. Thomas, W. I. 



The specimens examined by BENHAM were so much contracted that the above 

 measurements are probably incorrect. 



(2) Diachaeta littoralis, BEDDARD. 



Pontoscolex arenicola, SCHMABDA, Neue wirbell. Thiere, I, ii, 1861, p. 2 (in part.). 

 D. littoralis, BEDDARD, Ann. and Mag. Nat. Hist., Feb. 1892, p. 128. 



Definition. Length, 3 or 4 inches. Setae not ornamented, but bijid ; clitellar setae longer 

 and ornamented. Clitellum, XVI XXXI. Spermathecae, two pairs. Hal. Jamaica; 

 sea-shore. 



